, 2004). Elderly study participants had lower physical activity levels and did not consume whole-grain products, whereas the other groups stated regular consumption of fibre-rich products. Vegetarians and omnivores have significantly more copies of the butyryl-CoA:acetate CoA-transferase genes compared with the elderly (Fig. 2d). Although no clear correlation with Clostridium cluster IV and XIVa levels were found, the elderly tended to harbour fewer butyrate producers than did young individuals. Melt curve analysis showed that the butyryl-CoA:acetate CoA-transferase gene variant related to E. rectale/Roseburia

spp. is significantly more variable in vegetarians than in the elderly (Fig. 1a). Correspondingly, Clostridium cluster XIVa seems to be more abundant in vegetarians. Biagi et al. (2010) found lower quantities of Roseburia intestinalis, selleck screening library E. hallii and E. rectale in the elderly (>75 years)

than in young adults using the HITchip method. The abundance of the Clostridium cluster XIVa does not show significant correlations with the abundance of the butyrate gene variant as determined by melting curve analysis related to Roseburia/E. rectale spp., as this cluster also contains many nonbutyrigenic bacteria. As illustrated in Fig. 1a, the level of the melt peak attributed to F. prausnitzii was significantly SB203580 nmr lower in the elderly. This is of particular interest as this species has been reported to influence gut inflammation processes by exerting a Pregnenolone butyrate-independent anti-inflammatory effect (Sokol et al., 2009).

The vegetarian diet may have favoured growth of the Roseburia/E. rectale spp. that carries the butyryl-CoA:acetate CoA-transferase gene, without causing an increase in the abundance of butyrate producers in the entire Clostridium cluster XIVa. Omnivores and vegetarians had a similar potential to harbour butyryl-CoA:acetate CoA-transferase genes and members of Clostridium clusters IV and XIVa, possibly caused by a similar intake of fruit and carbohydrates. These results suggest that the elderly group in this study harbours less total bacteria and an even lower abundance of Clostridium clusters IV and XIVa. Together with a lower abundance of the butyryl-CoA:acetate CoA-transferase gene, the results indicate that in the elderly, microbiota may be characterized by a low butyrate production capacity. In respect of the important nutritive, anti-inflammatory and anticancerogenic potential of butyrate in the human colon, these findings demonstrate that these microbiota specificities may contribute to the development of degenerative diseases (Guigoz et al., 2008) and anorexia in advanced age (Donini et al., 2010). Consideration of the results of the analysis must take into account methodological limitations. Despite the extraction controls discussed in Materials and methods, DNA extraction can be influenced by diet and the consistency of faeces.